Lochinvar & A.O. Smith 100208485 Relay

The Lochinvar & A.O. Smith 100208485 Relay is a critical electromechanical switching component designed for high-performance hydronic systems. In the field, this relay is recognized as the direct manufacturer replacement for obsolete or legacy part numbers RLY2042 and RLY2042K. Engineers and technicians rely on this DPDT relay (Double Pole Double Throw) to manage high-amperage switching of blower motors, pump circulators, and internal control circuits within Lochinvar RF0500 boilers and A.O. Smith commercial water heaters. Its contact configuration ensures precise signal isolation, preventing back-EMF from damaging sensitive logic boards. When performing HVAC relay troubleshooting, swapping an aging 100208485 helps resolve intermittent "no-heat" calls or fan sequencing failures. This OEM Lochinvar replacement part features a standard plug-in or spade-terminal footprint for rapid installation during emergency service, ensuring the boiler relay switch maintains the integrity of the original furnace or water heater wiring factory specs.

• Universal Compatibility: Fully replaces legacy part numbers RLY2042, RLY2042K, and 100167653 without requiring modification.
• Precise Switching Control: Engineered to handle inductive loads in Lochinvar boilers, ensuring reliable fan and pump operation.
• Industrial Grading: Constructed for high-cycle environments typical of commercial A.O. Smith water heaters and large-scale residential hydronic units.
• Signal Integrity: Provides robust isolation between high-voltage power loads and low-voltage control circuits to protect the CCB (Central Control Board).

Is the 100208485 a direct replacement for the RLY2042K?
Yes, the 100208485 is the updated superseding part number for the RLY2042K. It is electronically and physically identical, designed to fit the same mounting footprint and terminal layout.

What are the symptoms of a failing boiler relay?
Common signs include a "clicking" sound without the blower or pump starting, intermittent operation of the fan motor, or the burner failing to ignite due to the control circuit not closing. If your Lochinvar RF0500 shows these symptoms, testing the 100208485 relay for continuity and contact resistance is the standard procedure.

Can I use an aftermarket general-purpose relay instead?
While general-purpose relays exist, using the OEM 100208485 ensures the coil resistance and contact ratings match the specific requirements of the Lochinvar control logic, preventing premature failure or fault codes.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.